Plant growth-promoting rhizobacteria (PGPR) is a beneficial group of free-living soil bacteria that colonize the rhizosphere and are helpful in root growth and development. PGPR plays an important role in plant growth through the production of phytohormones, solubilization of inorganic phosphate, increased iron nutrition via iron-chelating siderophores and volatile compounds that affect the plant metabolism and signalling pathways. Additionally, PGPR shows synergistic and antagonistic interactions with rhizosphere microorganisms and soil which indirectly improve and enhance plant growth rate. Various environmental factors affect the PGPR growth and proliferation in the plants. There are several shortcomings and limitation in the PGPR research which can be addressed through the use of modern approaches and techniques by exploring multidisciplinary research which combines applications in microbiology, biotechnology, nanotechnology, agro-biotechnology, and chemical engineering. Furthermore, PGPR is also known to reduce the emission of greenhouse gases (GHGs), carbon footprint, and also increase the nutrient-use efficiency. Here we describe the importance of PGPR in sustainable agriculture and their role in plant growth and development.